[Surgical result of 48 Bigelow myotomies for obstructive myocardiopathy]

Bigelow's myotomy is one of the surgical options available for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). The results of this operation were analysed in 48 cases operated between 1965 and May 1983. The average age of the patients was relatively low (38 years) but preoperative symptoms were severe (34 patients in Class III and 6 patients in Class IV of the NYHA Classification). The diagnosis was confirmed in all cases by echocardiography, carotid pulse tracings and cardiac catheterisation. 28 patients had associated lesions including 21 cases of mitral regurgitation (minimal in II cases, moderate in 6 cases and severe in 4 cases). All patients underwent Bigelow myotomy which was associated with a complementary procedure in 9 cases (including 2 mitral valve replacements and 2 semi-circular annuloplasties). The hospital mortality was 6 patients; surgical morbidity resulted from permanent intraventricular conduction defects (27 cases). At long-term, 3 more patients died, 2 from cardiac causes. Of the remaining 39 patients followed-up for an average of 32 months, functional improvement was marked, except in very advanced stages of the disease (Class IV) or forms with severe or uncorrected mitral regurgitation. The indications for Bigelow myotomy are discussed with reference to three parameters of HOCM (intraventricular pressure gradient, mitral regurgitation, decreased left ventricular compliance). This procedure has a beneficial effect on the subaortic stenosis and left ventricular compliance. It should be completed by mitral valve surgery in patients with significant regurgitation.